Conventionally, measuring instruments provide no digital or analog electrical output and the readings of the measurement instruments have to be read visually and recorded manually by users. It usually takes time and labor to do the reading and recording of the measurement data.
To overcome such an inconvenience in handling the readings of the conventional measured instruments, digital measurement instruments were developed to provide a direct connection with a computer system so as to eliminate the need of reading measurement result by eyes and recording it by hand. The digital measurement devices currently available in the market are very expensive and during operation, they allow only one channel to be activated each time. Besides, the state-of-art digital measurement instruments generally comprise a single chip architecture which limits the programmability and memory expandability thereof.
Due to the prevalent use of personal computers, it is therefore desirable to provide a digital measurement device which is embodied in a personal computer architecture, incorporating therein communication interface circuitry and peripheral interface circuitry, to provide the digital measurement device with easy programmability, memory expandability, low manufacturing cost and high efficiency and simultaneous activateablity of four or more than four channels for transmission and receipt of data.